This invention relates to a power source system for motor-operated vehicles in which it is possible to determine an actual power capacity, a maximum capacity at the current time point, of chargeable batteries such as Nixe2x80x94Cd battery, Nixe2x80x94MH battery, etc. for use as energy sources in for example electric motor-operated bicycles, electric motor-operated wheelchairs, electric motor-operated scooters, etc.
To control the residual capacity of a battery, it is necessary to learn the change in the actual capacity as the battery is used in cycles under different conditions. Detecting the change in the actual capacity is called xe2x80x9ccapacity learningxe2x80x9d. A general method of the capacity learning is to learn the capacity change from the discharge capacity from the fully charged status to a preset voltage. There are three types of discharge; the discharge on the device side, the discharge by refreshment, and the combination of the two.
In order to learn the capacity change by the discharge on the device side, it is necessary to discharge the battery down to the terminal state of discharge. However, in the case of devices that can cause problems when the battery is used to run down to the discharge stop, especially in the case of electric motor-operated bicycles for example, the battery is very rarely discharged to the discharge stop state. This makes it difficult to accurately learn the capacity in regular cycles.
And, in order to learn the capacity change by the refreshment discharge of the constant current and constant resistance type, restriction of cooling ability poses a problem: the discharge current must be set to a value much lower than that of a device (vehicle) in operation. A resultant problem of this is that accurate learning of the actual capacity is impossible depending on the state of deterioration (especially the deterioration due to increase in the internal resistance) of the battery. For example, while the current when the electric motor-operated vehicle is running is about 5 A to 27 A, the above-mentioned refreshment current is about 0.5 A. While the refreshment current can be increased by the increase in the cooling ability, it invites an increase in the cost.
The object of the invention made in view of the above is to provide a power source system for electric motor-operated vehicles, that makes it possible to accurately learn the actual power capacity.
As shown in a claim constitution diagram of FIG. 15, the invention of claim 1 is a power source system 402 adapted to learn an actual capacity, or a maximum capacity to be learned at a current time point when a chargeable battery 400 is used in cycles, characterized in that the system comprises; a discharging means 403 for performing refreshment discharge of the chargeable battery 400, a discharge control means 404 for controlling the discharging means 403 so that the refreshment discharge with the discharging means 403 is performed with a discharge current partially including a pulse waveform, and an actual power capacity learning means 405 for learning the actual power capacity of the chargeable battery 400 based on a discharge capacity including the discharge capacity during refreshment due to the pulse waveform current.
The invention of claim 2 is based on claim 1, characterized in that the actual power capacity learning means learns the actual power capacity of a chargeable battery on the basis of a sum of a travel discharge capacity determined by vehicle running and a discharge capacity determined by the refreshment.
The invention of claim 3 is based on claim 1 or 2, characterized in that the refreshment discharge is performed with a discharge current consisting of a part formed with a pulse waveform and a part formed with a constant current.
The invention of claim 4 is based on one of claims 1 to 3, characterized in that the discharge control means 404 controls the discharging means 403 so that the refreshment discharge is divided into two steps with the first step being performed with a pulse waveform current greater than the current of the second step discharge and with the second step discharge being performed with a constant current, and in that the actual power capacity learning means 405 learns the actual power capacity from the discharge capacity for the period ending at the end of the first step of discharge.
The invention of claim 5 is based on claim 4, characterized in that the discharge control means 404 controls the discharging means 403 so that the average discharge capacity (electric power) for the first step of discharge is nearly equal to the discharge capacity for the second step of discharge.
The invention of claim 6 is based on claim 4 or 5, characterized in that the discharge control means 404 switches the discharge from the first step to the second step when the battery voltage reaches a predetermined value.
The invention of claim 7 is based on one of claims 4 to 6, characterized in that the actual power capacity learning means 405 learns the actual power capacity of the chargeable battery in the case a previous charging is finished without interruption and in the case the number of charge and discharge cycles from the first or previous refreshment discharge is within a predetermined value.
The invention of claim 8 is based on one of claims 1 to 7, characterized in that the discharge control means 403 is provided with an external switch means for entering a refreshment requiring signal to the discharge control means 404 to make the discharging means 403 perform a refreshment discharge.